Avoid assertion violations in buf_bytepos_to_charpos

* src/marker.c (buf_bytepos_to_charpos): Disable the assertion
regarding bytepos always at the head byte of a multibyte
sequence.
1 job for master in 50 minutes and 4 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #965
test-all

00:50:04

 
Name Stage Failure
failed
test-all Test
Makefile:313: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
make[1]: *** [check-expensive] Error 2
Makefile:288: recipe for target 'check-expensive' failed
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:962: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1